Computer networks carry data between various devices. The data may be carried in connection-based links, such as the virtual circuits in an asynchronous transfer mode (ATM) network. Data may also be carried between devices in network segments where data is broadcast to all of a plurality of devices on the segment via a broadcast-type medium. An example of the latter is an Ethernet network. It is typically convenient to set up local area networks (LANs) using a broadcast type medium over which devices can share data.
In some circumstances, for example, where a LAN is required to connect devices that are geographically distant from one another, the LAN may be broken into separate segments. Within each segment devices (e.g., switches) can exchange data by way of a broadcast-type medium. The segments may be connected to one another by way of connection-based links such as physical transport lines. Such a LAN may be referred to as a virtual LAN (VLAN). The VLAN may be thought of as a logical web of connections over physical transports.
Metro-Ethernet networks are based on VLANs within the Ethernet network of a given metropolitan area. A VLAN is the interconnection of any number of access ports for a given customer within the larger service provider Ethernet network. Due to the nature of Ethernet VLANs as tree structures topologically, the calculation of the impact of any given port on the bandwidth (BW) of the underlying trunk network is complex since it depends not only on the BW of the port and the class of service (COS) of the VLAN, but also on the placement of the port within the context of the overall VLAN. Currently, expert technicians manage Ethernet VLANs manually. As VLANs become larger and include more complex (e.g., more COSs) it becomes more difficult and time consuming for technicians to take into account capacity considerations.